The debates. Team Romney had counted on the GOP convention as their opportunity to introduce their candidate to the country and shift the dynamics of the race permanently in his favor. That didn't work out. The only remaining events Romney can count on as moments when he'll have national attention are the three presidential debates in October. Romney will come in with a couple of built-in advantages. First, he has by some counts participated in more presidential debates than anyone in history (recall the never-ending series of them in the Republican primaries) and will be facing an incumbent who hasn't debated in years. Second, challengers get a stature boost from being on the same stage as the president.
The debates also mark the start of the campaign stretch run, raising the question of what kind of Hail Mary passes Romney and his advisers might toss if the race remains as intractable as it has been, whether Obama's convention bounce is durable or not. Keep in mind that this is a campaign that fabricated a welfare-related charge in August with the apparent aim of pressing race buttons. What will they do if they're behind in October?
Wild cards. Other unplanned or unforeseen issues—see "47 percent"—could pop up and dominate the campaign news coverage or even directly affect the course of the election. One predictable event: Romney has said he will release his 2012 taxes in mid-October, no doubt prompting a few more news cycles focused on why he hasn't released more—not what he'll want to be talking about.